Electrical heating or resistance unit



Dec. 4 1923. 1,476,116

H. A. THOMPSQN ELECTRICAL HEATING OR RESISTANCE UNIT Filed Feb. 24. 1921 nvvgzvrox.

*ATTORNEY.

Patented Dec. 4, 1923.

1 UNITED. STATES PATENT OFFICE.

'now'm a. mnonrsoN, or rrr'rsnunon, PENNSYLVANIA.

ELECTRICAL HEATING OB RESISTANCE UNIT.

. Application filed February 24, 1921. Serial No. 447,411.

Electrical Heating or Resistance Units, of

.which the following is a-specification.

, My invention relates to electrical heating or resistance units.

I will describe one form of unit embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is .a plan view showing one form of electrical unit embodying my invention. Fig. 2 is a sectional view on the line II-II of Fig. 1. Fig. 3 is a side view of the unit shown in Fig. 1. Fig. 4 is a view showing in side elevation the glass members of the unit shown in Fig. 1 before applyin the wire and assembling the members. ig. 5 is a plan view of the unit showing the relative positions of the glass members before they are fused to gether, portions of the upper plate being broken away to expose the parts beneath it.

. Similar reference characters refer to. similar parts in each of the several views.

Referring to the drawings, the unit comprises afn inner glass member 10, here shown as a flat plate, on which a coil of resistance wire 11 is wound. This plate is preferably provided with grooves 12 .to receive the strands of wire and to hold them in place,

' although such grooves are not essential and may in some instances be omitted.

' these two outer plates is a. strip 14 which inner plate 10 the length of this strip be- The inner plate 10 and wire 11 are pro- 'vided with an envelope of glass which, for convenience, will usuall be madeup of a number of members w ich are fused together during the process of manufacturing the unit. As'here shown, this envelope comprisestwoouter plates 13 and 13, each somewhat longer than the inner plate 10 but of thesame width as this plate. .Between lies adjacent one oft-he shorter edges of the ing equal to the width of the plates. At the other end of the unit the space between the outer plates is filled in' by glass strips as w follows. Next to-the inner plate 10 is a strip comprising'one longlmiddle section 15 and two short outer sections 15 and 15". Outside of this strip is a second strip compnsing a middle section 16 and two outer sections 16and 16". The combined length of each of these strips is equal to the width of the plates.

To assemble the unit, the wire 11 isfirst wound on the inner plate 10, and the ends are brought out at the left hand end of this plate. The inner strip ,is then placed in position against the left hand end of plate 10 with the ends of the wire between sections 15, 15 and 15, 15", respectively, whereupon the wires are bent around the outer ends of section 15 and brought towards the middle. Two metallic terminals 17 and 17 are then welded to the wire ends, each terminal preferably being drilled to receive the wire. The outer end strip is then placed in position with terminal 17 between sections 16 and 16?, and the other-terminal 17 between sections 16 The right hand end strip 14 is and 16. also placed in position against the edge of plate 10. The parts of the unit are then The unit which I have herein shown and 4 [described is well adapted foruse' as the heating element of a toaster stove. Units which are designed for other purposes Wlll, of course, be of various shapes, sizes and proportions, depehding on the nature of the ap aratus with which the unit is associated an on'the necessary character'stics of the unit.

Although I have herein shown and described only one form of electrical unit embodying my invention, it is understood that various change". and modifications may-be made therein within the scope of the a pended claims without departing from t e spirit and scope-of m invention.

Having thus descri d my invention, what I claim is: 1.'An electrical heating or resistance unit comprising a coil of wire embedded in pyrex glass.

2. An electrical heating or resistance unit comprising a coil of wire embedded in glass which will withstand quick changes of temperature through a wide range.

3. An electrical heating or resistance unit comprising an inner glass plate, a coil of Wire wound thereon, two outer gla$ plates located on opposite sides of the inner plate, and glass strips located adjacent the edges of the inner plate and between the two outer plates, the whole being fused together to form a mass of glass in which the wire is embedded.

4. An electrical heating or resistance unit comprising an inner glass member carrying a coil of wire and entirely embedded in glass.

5. An electrical heating or resistance unit comprising an inner glass member, a coil of wire wound thereon, and a surrounding envelope of glass members, the whole being fused together to form a mass of glass in which said wire is embedded.

6. The method of forming an electrical heating or resistance unit, which consists in winding a coil of wire on an inner glass member, surrounding the same'with an envelope of outer glas members, and fusing ner plate, a strip of glass located between said outer plates and alongv one end of the inner plate, a secondstrip of glass located between said outer plates and along the other end of the inner plate, said second strip being in three sections between which the ends of said wire are brought out, a third strip of glass next to said second strip and between the outer plates said third strip being in three sections, and terminals for said wire located between dissections of said third strip.

9. An electrical heating device comprising a resistance wire embedded in pyrex glass.

In testimony whereof I afiix my signature.

HOWARD A. THOMPSON. 

